Precision measurements of atomic g factor ratios using a dual species MOT

We describe progress toward a precision measurement of atomic $g$ factor ratios in a dual species MOT using a coherent transient technique referred to as magnetic grating free induction decay (MGFID)\footnote{I. Chan \textit{et al}., Phys. Rev. A \textbf{78}, 033418 (2008).}. In the experiment, a sample of laser cooled atoms is excited using two laser pulses with orthogonal polarizations. In a constant magnetic field, the MGFID signal exhibits oscillations at the Larmor frequency. Using a scheme in which both $^{85}$Rb and $^{87}$Rb atoms are simultaneously loaded from the background vapor into a dual isotope magneto optical trap (MOT), we measure the ratio of atomic $g$ factors between the $^{85}$Rb $F = 3$ and $^{87}$Rb $F = 2$ ground states by extracting the Larmor frequency from the MGFID signal.